Train control



July 9, 1929. F, 1 DQDGSON 1,720,645

TRAIN CONTROL Filed July 18, 1924 4-Sheets-Sheet l ff WM/jm @A TToRNEY F. L. DODGSON TRAIN CONTROL July 9, .1929.

Filed July 18, 1924 4 Sheets-Sheet 91 SZ GO 93 B47 INVENTOR ATTORNEY July 9, 1929. F. L.. DODGSON TRAIN CONTROL Filed July 18, 1924 4 Sheets-Sheet u. A N TL I Ik tu Botte. Prfcoo EPF Y YJ-uly 9, 1929. F. L. DODGSON TRAIN CONTROL Filed July 18: 192,4 4 Sheets-Sheet FIG. 5.

O Fo I..

Non-Trdm Conf rol Terrvfory fx T oRNEY f Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

FRANK L. DODGSON, OF ROCHESTER, NEW YORK, ASSIGNOR TO GENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK.V

TRAIN CONTROL.

Application filed July 18,

This invention relates to train control systems tor railroads, and more particularly to such a system ot the type commonly known as the intermittent inductive type.

In accordance with this invention, it is proposed to comniunicate or transmit controlling influences from the trackway to a moving train by means ot an inductive or .non-physical action or cooperation between elements located on the train and elements located at spaced points along the trackway, and to impose, by means ot the influences so transmitted, a predetermined speed limit, varying in accordance with changes in trailic conditions ahead, which the train can not exceed without an automatic brake application.

It is advantageous in train control systems to supply the controlling intluences with the use ot as little electrical energy as possible, particularly7 in connection with the trackway equipn'ient, in order to minimize the expense ot wayside transmission lines, relays and the like, as well as to reduce the power consumption to a minimum. In order to accomplish this` and other desirable objects, it is contemplated in the. present invent-ion to employ trackvay elements which will operate to change themagnetic circuit et inductive carried elements when brought into close. proximity thereto, said trackway elements requiring no energizing current. lith such inert track elements, it has been found that a certain relative movement ot' the track and the car-carried elements must occur in order that an appreciable impulse may be transmitted. From this it is obvious that, if the vehicle passes over a trackway element below some certain low speed, no control influence will necessarilyv be received. For a sate speed control s vstem, however, it is essential that the sate speed limits should always be set up whenever tratlic conditions require it, irrespec-tive ot the speed at which the train may pass the controllingl track device.

Also in an intermittent type of train control system, it is desirable to make provision so that. whenever the train stops, it can not thereafter proceed faster than some restricted minimum speed until a resetting or restor- 1924. Serial No. 726,781.

ing impulse, indicative of sate tratlic conditions, has been received. For example, a train may pass a block signal indicating clear, and tor some reason come to a stop in the block, and while stopped, a switch may be opened, or a train back into the same block or the next block in advance, setting up danger conditions. In such a case, it will be evident that. the interest ot' safety would best be served by requiring the train that has stopped to proceed at a restricted minimum speed until, upon reaching the end ot the block, it comes again under the automatic control of the trackway equipment.

In view ot these and other considerations,

`it is proposed in accordance with this invention to provide automatic apparatus which acts to set up a restricted speed limit both on the reception of a stopping influence from the traekway and also whenever the train comes to ay stop, or slows down below some ver)v low speed, such as 3 miles pei' hour, this minimum speed limit being continued until a resetting impulse is received from the trackway.

By reason ot the feature of setting up a minimum speed whenever the train stops, it becomes necessary to eliminate this automatic itunction otl the system whenever the train is ti-avellingr in territory not equipped with reset track devices, otherwise the train could not operate in territory not equipped for train control purposes. A further object of the invention, therefore, is to provide suitable means for rendering the car-carried apparatus inactive to impose the minimum speed limit while the train is travelling in unequipped territory.

A still further object of this invention is to provide means by which the train operator or engineer is forced to acknowledge changes in tratiic conditions as indicated by wayside sign als, otherwise some penalty or inconvenience is imposed upon the engineer if he fails to acknowledge such signals, thereby stimulating or enforcing his vigilance.

Further objects, advantages, and characteristics of the invention will become apparent as the description ot the system progresses.

In describing the invention in detail, reference will be had to the accompanying drawings in which Fig. l represents the section of trackway equipped tor automatic train control embodying the present invention, the trac-kway devices and circuits having been diagrammatically shown;

Fig. 2 is a simplified and diagrammatic showing ot' the car-carried apparatus comprising a part of the speed and distance governed elements;

Fig. 3 shows in a simplified and diagrammatic manner the circuits ol the car carried apparatus Fig. 4 represents a section ol trackway equipped with apparatus l'or making a change from trackway territory equipped for automatic train control to unequipped territory; and

F ig. 5 shows the trackway equipment and a portion ot the car-carried apparatus including alternative means for making a change from equipped to unequipped territory.

Trac/merry appufmlfua-leterring l'irst 'to Fig. l, a railway track has been represented. by the rails l divided into blocks by the insulating joints 2; and the block l and the ends of two adjacent blocks H and Ql have been shown. As the trackvay devices and the vcircuits used in the several blocks are identical, a detailed description of one block only will be given, corresponding elements in the adjacent blocks being referred to by like reterence characters having distinctive `exponents.

The usual track battery 3, for supplying track circuit lcurrent is connected across the rails at the exit end ot the block. A direct current track relay 4 ot a type well known in railway signalling practice is connected across the rails at the entrance end of each block, receiving its energizing current from the battery 3 through the rails.

Wayside block signals, taking the torm of semaphore or light signals, or any other type of signal., are preferably used; and for the purpose ol illustration, signals ot Vthe semaphore type have been represented in a conventional manner at Z, without attempting to show their .control circuits.

A train control operating inductor O is located at one side of the track rails near the exit end of.' each block and at least at safe braking distance for the maximum speed limit trom the wayside signal at the exitI end oi' the next succeeding block. This inductor Q comprises a substantially U-shaped iron core 5 having pole pieces 6 and carrying a winding 7. The core 5 is preferably made oi laminated iron. The winding 7 ot the operating inductor O is normally in a closed lcircuit of low resistance through the iront contact S of a line relay 9 which is energized through a circuit identical with the energizing circuit for relay 9 Which may be traced as -follows rom battery terminal C, through the winding ot relay 90, front contact l0 et track relay Il, wire ll, contact 121 ot track relay ell, to battery terminal B.

A train control reset mae'net R is located near the exit end o'l each block on the opposite side of the track rails from the operating inductor O. The construction ot tnis reset magnet is similar to that of the inductor U, except that the windings and 'cores may be designed for different currents and fluxes. The winding 13 ot reset magnet R for the block l is normally energized trom the battery l-l through a circuit including the front contact l5'l o'l track relay l1 et the block J next in advance, as clearly shown in the drawin W'hen the block J' next in advance is occupied and its track relay l1 cle-energized, the winding i3 of the reset magnet R for the block is short-circuited, that is, is included in a deenergized closed-eircuited of low resistance through the ,back contact finger ll oit the track relay Ll. ln order to reduce the current consumption i'or the reset magnets, an approach relay oi the usual construction, connected in series with the track battery, may be it is obvious that it a train is in the block I, its wheels and axles will shunt the track circuit in the rails and tlc-energize the track relay 4t. This will open contacts l0, l2 and l5, tlc-energizing relay 90, and opening the energizing circuit to reset magnet R".

Although the reset magnet it has been shown energized with direct current, it is to be understood that alternating current is equally adaptable for this purpose, and may be used in practice when available.

@wr-carried apparenza-A railway vehicle is represented by a pair ot wheels and axles 16. This vehicle carries two receiving devices, an operating receiver R() and a reset receiver RR. These receivers are in the torni of U-shapcd cores, preferably made ot' laminated iron, the operating receiver RC carryin two windin S and l?, and the reset receiver carrying two windings 8S and 89, as plainly shown in the drawings.` rlhese receivers are located on the vehicle in position to travel over and in inductive relation to the trackway operating inductor and reset magnets, respectively. The connections to the coils oit' these receiving devices will be explained as the description progresses. The air-gap between he receiver RO and the operating inductor O is positioned a short distance, such as 3 inches, above the level ot the top ot the track rails, so as to avoid improper' action of crossing rails andthe like upon the receiver.

According t-o the preferred arrangement, the operating inductor O controlling train movement into a given block is located approximately braking distance for the minimum speed limit (assumed to be 2O miles per hour) in the rear of the entrance to said block, in order that a train approaching said block in the occupied or danger condition may be stopped safely short of the entrance to such danger block, if the engineer fails to acknowledge upon passing said inductor. The reset magnet R, associated with each block and controlled by its track circuit, is located in the rear ofthe corresponding operating inductor O, so as to be first encountered by a passing train.

'As shown, the car equipment is organized for movement of the locomotive or other vehicle with one particular end leading, so as to bring the operating receiver RO on the righthand side of track; but `in practice arrangements may be made, by the use of a reversingswitch connected to the car wheels or similar means, to change over the connections between the coils of the receivers RO and RR and the car relays, so that the car may be operated either end leading. lilith such a reversing switch, such as shown, for exan'iple, in the application of C. S. Bushnell, Ser. No. 544,561, filed March 17, 1922, the operating receiver is always on one side (shown as the right-hand side) of the car with respect to its direction of movement. lYhen the car is travelling opposite to the normal direction of traffic, thereset magnets R will not act upon the operating receiver RO, because for such 'train movement these reset magnets are on closed circuit. For single track railroads, duplicate sets of operating inductors and reset magnets are used for traflic in opposite directions, the set for each direction being controlled in accordance with the indications of the corresponding block signals.

Fig. 2 is a simplified showing' of a part of the car-carried equipment. A drive shaft 17 is geared to or driven by other suitable means from the wheels of the vehicle. Mounted on this shaft 17 is a centrifugal speed-responsive device or centrifuge Gr. This centrifuge G may take any one of a number of preferred forms, but is illustrated in a simplified form for the sake of clarity. A-[ixed collar 18 and a slotted movable collar 19 are mounted on the shaft 17 and are urged apartby the spring 20. The collars are connected by links 21, 22, 23 and 24, carrying weights 25 and 26 as shown. The slotted collar 19 engages the end of a lever 27 which is connected to a speed shaft 2S. It is obvious that as the speed of the vehicle increases, the weights and 26 will be thrown outwardly, depressing collar 19 and drawing down the arm 27 against the action of the spring 20, thus rocking the speed shaft 28.

The speed shaft 28 is used to open and close a number of contacts for different ranges of speed. A typical speed contact unit is shown in Fig. 2, and comprises a pair of contacts 146, one of which is a resilient finger, tending to move away from a stationary contact, represented by an arrow. The resilient finger carries a roller, bearing against the edge of a cam 62. It is evident that by properly shaping the edge of the cam 62, the contacts may be closed for any desired range of speeds and opened at other ranges. The unit shown in Fig. 2 is adapted to close its contacts for speeds from Zero to 5 miles per hour.

Rigidly secured to the drive shaft 17 is a worm gear 30 engaging a worm wheel 31 which is rigidly secured to a shaft A pinion 33 fixed on the shaft engages two large gear wheels 34 and 35 carried on fixed pins or shafts 36 and 37. Two bifurcated arms 3S and 39 are also journalled ou the pins 36 and 37, these arms carrying pinions 40 and 41 which engage the worm wheels 34 and 35, respectively. The free ends of the arms 3S) and 38 are held down by a cam starter magnet CS and by a distance starter magnet DS. respectively, against the up 'ard pull exerted by two springs 42 and 43. Directly over and in alignment with the pinions and 41 are two mutilated gears 44 and 45. lVhen the magnets DS and CS are deenergized, the arms 38 and 39 are lifted by the springs 42 and 43, and the pinions 40 and 4l engage the mutilated gears 44 and 45, driving them from the drive shaft through the gear train just described.

The mutilated gear 45 drives a shaft 46 carrying a permissive speed cam 47 which operates the upper end of a floating lever 49, the opposite end of which is operated from the speed shaft 2S through a lever 50. It will be seen that the movement of the floating lever 4f) ust described is dependent on a function of the speed of the vehicle and the distance it has traveled from the point at which lthe cam-starter magnet CS was deencrgized.

A specially shaped speed-distance cam 51 is connected by a link 52 to a point near the middle of the fioating lever 49. This cam 51 is biased by a spring 53 and operates contacts 54 and 55 which are connected in control circuits as hereinafter described. The mutilated gear 44 drives a distance shaft 56.

The dist-ance shafts 4G and 56 are used to open and close a. number of contacts at different distances of travel from the point at which these shafts are. started by the deenergization of their magnets CS or DS. One distance contact unit is shown on each of these shafts in Fig. 2. Each distance unit comprises a pair of contacts, consisting of a resilient finger tending to move away from a stationary finger, the resilient finger carrying a roller which bears against t-he edge of a. cam as shown. By properly shaping the edge of the cam, the contact-s may be opened at. any distance of travel from the point at which the associated distance shaft was started. The distance contact unit 48 on the shaft 46 is adapted to open its contacts immediately on the initiation of the distance shaft 16, while the unit 57 is adapted to open its Contact at a point about 1000 feet ot car travel from the point at which the distance shalt 5G was initiated. The shatts 5G and 46 are returned to their normal positions by means ot the springs 5S and 59.

Referring now to Fig. 3, a diagrammatic view oit the car circuits and devices has been shown. rThe secondary coil S ot' the operating receiver RO operates a primary relay PT and a secondary relay ST. These relays are pre'lerably of the quick acting` type having movable armatures centrally pivoted which are biased by springs 158 and. 159 as shown to move 'troni the horizontal attracted position to an inclined retracted position indicated by dotted lines. These arniat-ures when retracted open iront contacts shown conventionally as arrows. A reset relay RT is connected to the reset receiver RR and a cam control. relay is provided, being connected as hereinafter described. I These relays have double centrally-pivoted armatures and Gl, similar to the armatures ot the relay PT, vthe opposite ends ot' which are insulated from each other by the insulating blocks 601 and G11.

An acknowledging relay Ack. a non-control relay NC, a penalty relay PR, and a low speed relay LS are also provided. These relays, as well as the relays PT, ST, CC and KT, are ot a type suitable tor train control practice, and are provided with normally biased contacts so mounted as to be unatfected by the vibration or swaying ot the train.

Mounted on the speed sha'tt 28 which is represented in Fig. 3 by a dot-and-dash line, are seven speed cams G2 to 68, inclusive. These cams close cont-acts at diill'ercnt ranges of speeds, the speeds at which the several contacts are held closed being indicated on the drawings. The distance shaft t6 carries three distance cams 69, 7 0 and 1S. These distance cams are designed to close or open contacts after a certain distance oit travel from the point at which the cams are started, as will be hereinafter explained. The distance cam 57 carried on the shaft 5G operates to open contacts 71 and 72 a'tter the vehicle has moved a given distance, assumed to be 1,000 feet, trom the point at which this cam 59's' is started.

An electro-pneumatic valve EPV is provided tor the purpose oit applying the brakes in response to certain control influences. This electro-pncumatic valve EPV may be ot any s 'table type and is pre'lcrably ot the typo which acts to apply the brakes when the circuit thereto is broken. This may be done by venting the brake pipe directly, by moving the regular engincers brake "alve, or in any other suitable manner, but the control ot the electro-pncumatic valve is preferably so arranged that it cannot be operated manually by the engineer.

Oar circuits-For convenience and in order to simplify the drawing, the letters B and C have been used to indicate battery terminals et diltcrent polarity. All circuits have been shown in their normal condition, that is, the positions oft all contacts and cams are those which would be assumed with the vehicle running above the minimum but below the maximum speed limit, and under clear tratlic conditions ahead.

The penalty relay PR is normally energized through a stick circuit which may be traced as follows z-rom the battery terminal C, through primary winding l), wire T3, through the winding of penalty relay PB, wire Til, contact T ot penalty relay PR, wires 76 and T7, contacts 78 oit speed cam 65, wires 7 9 and 80, contacts 71 and 72 ot distance cam 57, wire Sl to movable contact 82 ot secondary relay ST which is connected to battery terminal B.

lt should be noted that, as the penalty rel ay PR is energized through a stick circuit incl u ding the primary winding P et the operatin receiver RO, a break in the primary winding circuit will cause the deenergization o't the penalty relay'PR, and an automatic brake applic-ation will result as hereinafter described. 'lhus a check is maintained on the primary winding P against the opening ot its circuit.

The secondary winding S of the operating receiver RO is connected to the winding ot primary relay PT through a stick circuit which is obvious from the drawings.

The reset receiver RR has two windings 88 and 89 connected. in series; and these windings are directly connected to the winding of the reset relay RT through wires 148, 149, 90 and 91. The movable contact 97 of the reset relay RT closes a circuit through the winding of this relay, as clearly shown in the drawings. This circuit comprises the winding ot the relay RT and the contacts 97 ot this relay in series,vand does not include any source ot energy aside from the energy stored inthe magnetic tield set up in this relay RT.V ln other words, when the relay RT is picked up in response to an influence transmitted from the trackway, this relay closes its contact 9T thereby short-circuiting its winding and thus causing this relay to be slow to drop, that is, this relay wil be held up until the energy stored in its magnetic field has been dissipated in the short-circuited winding o'l the relay.

The low speed relay LS is energized through a pick-up circuit which may he traced as follows trom battery terminal B, through contact-s 98 oit distance cam 18, wires 99 and 100, winding ot low speed relay LS and wire 101 to battery terminal. C. A stick circuit for this low speed LS may be traced as tollowsz-trom the battery terminal C, through the winding of low speed relay LS,

wires 101, 100 and 102, contact 103 of relay LS, wire 104, contacts 105 ot speed cam 66 to the battery terminal B.

The cam control relay CC normally energized through a circuit which may be traced as follows :-t'rom the battery terminal B, Contact linger 82 and trent contact of the secondary relay ST, wire 135, iront contacts of the relay CC, wire 94, the winding of the rclay CC, wire 95, contacts 96 of the cam G3 to the battery terminal C.

The electro-pneumatic valve EPV is normally energized through a circuit which may be traced as follows r--from battery terminal C through the winding ot' the electro-pneumatic valve EPV, wires 106 and 107, contact 108 o1 the penalty relay PR, contact 100 ot' low speed relay LS, wire 110 and contacts 54 and ot the speed-distance cam 51 to battery terminal B.

The remainder of the car circuits will be apparent or pointed out as the operation of the system is explained,

lllaarm/ufnb speed Zim/ nuclei" dem zf/af/c coladzn3-lvhen a train is operating under the control ot' the system as shown under clear tratlic conditions ahead, a maximum speed limit., assumed to he miles per hour, is imposed. Relier-ring to Fig. 2, it is evident that with the permissive speed cam 47 in the position shown, the train speed cannot exceed a certain amount, depending on the radius oit this cam, without opening the contacts 54 and 55 and so causing an auttunatic brake application by the deenergization ot' the electropneumatic valve EPV. The permissive speed cam 47 and the speed distance cam 51 are assumed to be so designed and proportioned that this automatic brake application will occur at a speed of G0 miles per hour. viren the train speed drops bel-ow the maximum speed limit, the engineer may release the brakes on account ot the re-cnergization of the electro-pneumatic valve EPV through the contacts 54 and 55.

Enter/Ing (a. cautionbZO0c.-Assu1ning that a train is located in the block J, the track current in block l is cut ott by the wheels and axles ot said train, and hence the track relay 41 at the entrance end oit this block deenergized and will open its front contacts 101, 121 and 151. The opening of contact- 121 deenerthe line relay 90 at the exit end ot block ll, opening its contact S", and thus ln'eaking the circuit tluough the coil ot operating inductor O. Reset magnet R0 at the end of the block H is then energized through a circuit which apparent from the drawings.

A following train lirst passes over the energized reset magnet R0. 'The flux trom this ret will pass through the core of reset itil. energizingI its coils 8S and 0 Ov, :uoinentary energizing the reset. relay RT through a circuit which is obvious. The armature of the reset relay RT will be at.- tracted, but there will be no further effect on the car apparatus, as the cam control relay CC is already energized as shown in Fig. 3.

The train will next pass over the operating iiuluctor O. As the circuit through the coil 7 is open, the inductor acts as an iron bar momentarily placed across the poles ot the operating receiver RO. duces the reluctance ot the magnetic circuit through the core of the operating receiver, causing` a surge of flux in this core. This increase or Surge of flux will, according to well-known laws ot electricity, induce an electro-motive-torce in the coil S, tending to oppose the current normally flowing in this coil and in relay PT connected thereto, and so cause a momentary reduction of the value ot this current. The primary relay PT is so adjusted that this momentary reduction of current through it causes it to release its armature 111 and so break its stick circuit, and also the circuit through the winding otl secondary relay ST. As the operating receiver RO passes away from the operating inductor O, there is a reduction of flux in the core of receiver RO and 'a corresponding increase in electro-motive-force in the coil S, but since the primary relay PT has opened its stick circuit, this induced electro-motivetorce will have no ell'ect.

The deenergization ot the secondary relay ST causes its armature 82 to be retracted and so deenergizes the cam control relay CC, releasing its armature 61, the energizing circuit for the relay CC having been traced above. This breaks a circuit to the cam starter magnet CS clearly shown in the drawings, and starts the cams 69, 70, 47 and 48 in a manner point-ed out above.

The deenergization ol the secondary relay ST also makes a break in the stick circuit for the penalty relay PR which circuit has been traced above. It, however, the engineer' has recognized the wayside caution signal and is diligent, he dcpresses the push button PB and so energizes the acknowledging relay Aol: through a circuitI which is clearly shown, such energization of the acknowledging relay Aula completing an alternative circuit through the penalty relay PR which may be traced as follows: starting at battery terminal C, through primary coil P of operating inductor RO, wire 73, winding of penalty relay PR, wire 74, contact of the penalty relay, wire 7 (i, front Contact 112 of acknowledging relay Ac/u, wires 113 and 80, contacts 71 and 72 ot distance cam 57, wire 114, cont-act 115 of acknowledging relay A07: to battery terminal B.

It' the engineer recognizes the caution signal, and operates the push button PB before passngthe active inductor O0, `the penalty .relay PR is maintained energized in `spite of This momentarily reary relay ST. The engineer must operate venergizes the secondary relay ST.

the opening of front contact 82 of the secondthe push button before the secondary relay ST is deenergized, otherwise the stick circuit of the penalty relay PR is opened; and in this case the penalty relay cannot be re-energized to permit a release of the brakes until the train is stopped, as hereinafter described. Therefore, the engineer must at all times keep alert and watch the trackway for the indications of the block signals.

After the train has traveled a short distance, such as 100 feet, the distance shaft le is turned far enough so that the distance cam closes its contacts 80 and 87, establishing a pick-up circuit 'for the primary relay PT. Attraction ot' the armature of the primary relay PT as will hereinafter be described re- The engineer must keep the acknowledging relay Ack energized duringl this distance of travel, or until the secondary relay ST is re-energized to establish the normal stick circuit for the penalty relay PR. The cam control relay CG remains deenergized, since its normally closed energizing circuit through the front contacts of the secondary relay ST is opened at its own front contact.

If for any reason the engineer has failed to acknowledge the caution signal the penalty relay PR becomes deenergized, opening its front contact 108, and so deenergizing the electro-pneumatic valve EPV, thereby applying the brakes and bringing the train to a stop. After the train has been brought to a stop, the contacts 11G of the speed cam Get are closed, and the penalty relay PR may be reenergized through the following circuit loeginning at battery terminal B, through contacts 11G of spe-ed cam (311, wire 117, winding of penalty relay PR, wire 78, primary coil D of operating inductor RO to battery terminal C. The normal circuit through this penalty relay traced above, will not be closed, because the speed contacts 78 are open at the low speed of less than one mile per hour at which speed contacts 11G are closed. It therefore Vbehooves the engineer to operate the acknowledging push button PB to energize the relay A075, which relay if once energized will remain energized so long as the train speed does not exceed 5 miles per hour through the stick circuit including speed contacts 140, thus maintaining the contacts 112 of the relay Acli: closed. With contacts 112 closed the relay PR will, if once picked up, be stuck up through the following circuit ,'beginning at the terminal of a battery, contact 82 of the relay ST, wire 81, distance contacts 71-72, wires and 113, contact 112 of relay Ack, wire 70, stick contact 75, wire 741, winding of the relay PR, wire 78, primary coil P to the common return wire C connected to the other termina-l of said battery. From this it will appear that if the speed of the train is gradually increased the speed contacts 78 are closed as soon as the speed of the train is above 3 miles per hour, thus shunting the contacts 112 of relay A070 and re-establishing the normal stick circuitfor the relay Pit shown closed in Fig. 3. It also appears it the train speed is further increased that the contacts 146 will open when the train speed eziceeds 5 miles per hour thus breaking the stick circuit for the relay Ack, thus causing deenergizing of this relay A073 and opening of contacts 112. It should be noted that the increase in train speed to tive miles per hour or over must be accomplished within 17.000 feet of travel after the energization of Ack, since as will appear below, at the end of 1,000 feet of travel after DS is deenergized, 71, 72 will be opened to again cle-energize PR. This condition results from the fact that the en-ergization of A073 raises 115, causing the (le-energization of DS and the opening of '7172 after 1,000 feet of travel of the vehicle as described below). It is to be understood, also, that the increase in train speed to live miles per hour or over must not be accomplished within less than 100 feet of travel from the point at which A077: is energized, since the pick-up circuit for PT cannot be closed until contacts 86-87 have become closed. The pick-up circuit for PT will be traced presentl'f.

1n order that the engineer may not abuse the use. of the acknowledging device by holding or fastening the push button PB down, a distance operated cam 57, operating contacts 71 and 72, is provided. lWhen the acknowledging` relay Ackl is energized, the back contact of its linger 115 opens, deenergizing the distance starter magnet DS through a circuit which is clearly shown in the drawings. This starts the distance cam 57 which, after 1,000 feet of travel, opens the contacts 71 and 72, thus breaking the normal stick circuit for the penalty relay PR and causing an automatic brake application as described above.

After a given distance of travel in caution territory, assuming the engineer to have pressed the acknowledging push button PB, assumed to be 100 feet from the point at which the distance cams were started, the cani 70 closes its contacts 8G and 87, re-energizing the primary relay PT through a circuit Awhich may be traced as follows trom the battery terminal C, through secondary winding S of the operating receiver BU, wire 88, winding of the primary relay PT. wiresl 84 and 85, contacts 86 and 87 of the distance cam 70, to the battery terminal B. They secondary relay ST will also be re-energized attracting the armature 82 and closing the stick circuit to the penalty relay PR.

The train will now proceed in the caution block with the permissive speed cam i7 revolving', and so imposing a tapered speed re.-

.striction on the train as defined by the shape of this cam.

Leaving caution Noale-If, when the train approaches the exit end of block I, there is no train in the next two succeeding blocks, the reset magnet R will be energized, and as the reset receiver RR passes over this energized reset magnet, a current is induced in the coils 8S and 89 of this receiver. This induces a current in the reset relay RT, attracting its armature and re-energizing the cam control relay CC through a circuit which may be tracedas follows from the battery terminal B, through the movable contact 92 of the reset relay RT, wires 93 and 94 through the winding of the cam control relay CC, wire 95, contacts 96 of .the speed cam 63 to battery terminal C. The contacts 9T of the reset relay x-T short-circuit the windings of this relay when the armature 60 is attracted, thus making this relay slow acting so that it will not release before the cam control relay CC has attracted its armature and is energized through its stick circuit. The re-energization of the cani control relay CC causes its armature to close its contact 11S and re-energizes the cam starter magnet CS through a circuit which is clear from the drawings. The pinion 41 will now be released from the mutilated gear 45, and the spring 5S will. return the distance shaft 46 to its normal position. The train may now proceed under a maximum speed restriction until further changes in traffic conditions are communicated thereto.

Assume now that the train approaches the end of block I with its controls in the caution position as described above, and that caution conditions exist in the block J. Under these conditions the reset magnet R is energized, and the circuit through the coil 7 of the operating inductor O is open, placing this inductor in the active condition. The reset relay RT is first energized from the reset magnet. R through the reset receiver RR, placing the cams in the normal position as just described above. The operating inductor O impresses an impulse on the operating receiver RO and drops the primary relay PT, starting the cams in the same manner in which they were started at the entrance to the caution block and requiring acknowledgment as described above. Thus it is clear that on passing from a danger block to a caution block, the operation of the automatic train control apparatus is the same as its operation on entering the caution block from a clear block, except for the fact that the cams are first set in their normal position before being started by the operating inductor O.

Enter/ag Zanger Node-Assuming that the train is proceeding under caution control'conditions and approaches a block in which another 'train is located, that is, in which danger traffic conditions exist, the reset magnet R is deenergized and the cams are not returned to normal. The operating inductor O is in its active condition and acts to drop the primary relay PT, requiring acknowled gment as described above. Thus, on entering a danger block from a caution block, the cams G9, 70, 47 and 48 being already run down, remain down as the train proceeds into the danger block from the caution block, maintaining the minimum speed limit on the train.

On passing from a caution to a danger block, the cam shaft 46 is run down, and its movement cannotbe used to restore the primary relay PT to its normal position. lVhen the cam is run down, its contacts S6 and 87 are open, but due to the difference in radii of the concentric portions of this cam, the contacts 86 and 119 are closed; and, if the acknowledging push button PB is depressed, energizing acknowledging relay Acli, the primary relay PT will be re-energized through the following circuitt-starting at b ttery terminal B, through contact 12() of the aninowledging relay, wire 121, contacts 119 and S6 of cam 70, wires 85 and S4, winding ol primary relay PT, wire S3, secondary winding S of operating receiver RO, to b atterv terminal C.

It should be noted that whenever the primary and secondary relays PT and ST are deenergized, the stick circuit through the penalty relay PR must be maintained closet through a circuit including front contact 115 of the acknowledging relay Ack to prevent automatic brake application and subsequent low speed restriction. Tn other words. the engineer or train operator must register his vigilance by performing the manual act of acknowledging'whenever a caution or a danger signal is passed.

LowsiectlcoiitroZ.-Tl1e foregoing description of the operation of the system has been made on the assumption that the train under consideration is travelling above a low speed limit, assumed to be 3 miles per hour. It has been found in practice that the type of receivers described above will not operate successfully below a given low speed. For this reason it is necessary, in order to maintain constant control of the train. to provide means for imposing a low speed limit whenever the train speed is allowed to drop belowY the safe operating speed of the receivers.

Tu au intermittent system, \\herever a train is brought to a stop at some point in a block, it is considered good practice to restrict the subsequent movement of the train to a minimum speed until an impulse coiresponding to clear tratlic conditions ahead is received. This is considered desirable for the reason that traffic conditions in the block might have become unfavorable while the train was at a stop. For instance, another train may have entered the block or the block in advance from a siding, or may have backed into either' ot these blocks, and these dangerous conditions could not be transmit-ted to the train under consideration until the trackway inductor at the end ot the block was passed.

W'hen the train speed drops below the speed limit below which the reception ot an adverse control influence is not relied upon, assumed to be 3 miles per hour, the speed .cam 63 will open its contacts 96, deenergizinfl the cam control relay CC which in turn deenergizes the cam starter magnet CS through circuits which are obvious from the (lrawings, and starts the distance cams (39,

70, and lS. The speed cam 65 operates to open its contacts 78. This breaks the stick circuit for the penalty relay PR, unless the acknowledging relay AC: is opera-ted to close. an alternative circuit ior the penalty relay through the contact 112. rlhe speed cam 66 operates to open its contacts breakingl the stick circuit to the low speed relay LS, which circuit may be traced as follows ztrom the battery terminal B, contacts 105 of cam G6, wire 104, contact finger 103 and t'ront contact ol the relay LS, wires 102 and 100 and the winding ot the relay LS to the battery terminal C. After the distance cam 418 has started and opened its contacts 98, the energizing` circuit tor the low speed relay LS through these contacts 9S andthe wires 99 and 100 is broken`r causing the contact lingers 103 and 109 of this relay to drop. This throws the control oit the electro-pneumatic valve EPV from contacts 54 and 55 of the speed-distance cam 51 through. the wire 122 to the contacts 123 ot the speed cam G7. The contacts of the speed cam 07 are maintained closed at train speeds ot 'from zero to 20 miles per hour, so that the train may now proceed under this speed restriction until the distance cams are reset. It should be noted that in order to energize the electro-pneumatic valve through the contacts 123 ot' the speed cam 67, it is necessary that the contact 121i ot the acknowledging relay be closed, provided the speed o'l the train is below 3 miles per hour. For this reason the aclinowledging relay must be maintained energized until the train speed is in excess oit 3 miles per hour at whichtime contacts 125 ot speed cam GS are closed and shunt the contacts 124-., thus maintaining a circuit through the electro-pneumatio valve which may be easily traced as follows, closed :--starting` at the terminal B, contacts 125, contacts 123, back contacts 109, contacts 108, wires 10'? and 100, winding ot the brake control device EPV, back to the common return wire C. In order that the engineer need not manually maintain the acknowledging relay Ack energized until the train speed is above 3 miles per hour, a stick circuit for the acknowledging relai, through contacts 146 of the speed cam 62, closed from zero to 5 miles per hour and front contact ot linger 1l? ot the acknowledging` relay fic/c pirovided.

vFrom the above it is evident that, whenever the engineer allows the train speed to drop below 3 miles per hour, the autoinatic control formerly imposed by cam 51, is rendered inactive, and a new restrictive control is imposed by cam (37. It should also be noted that, in order to avoid the de-energization ot' the penalty relay PR and an immediate automatic brake application bringing the train to a. stop, the engineer must operate the acknowledging; push button PB whenever the train speed drops below 3 miles per hour. rlhe restrictive minimum speed limit continues unt-il the train reaches an energized reset magnet which energizes'the reset relay RT, and results in the re-energization of the cam starter magnet CS and the restoration ot the cams as hereinbeitore described. It the cam shatt 4G is restored to its normal position, contacts 98 are closed, establishing a picleup circuit 'for the low speed relay LS, which then remains energized through its stick circuit until the speed again drops below 3 miles per hour. TNhen the low speed relay LS re-enern'ized, the control ofthe brakes is dependent upon the penalty relay PR and the speed-distance cam 51.

rllhe low speed relay LS and its control as just described, requires that every time the train stops or drops below 3 miles per hour, it cannot thereafter proceed at a speed greater than the minimum speed of 20 miles per hour until the active reset magnet is passed. This means that whenever a train stops in the middle ot' a block it must run at a restrictive speed to the end ot that block where it can encounter an active reset magnet. Ordinarily this does not impose any objectionable restrictions upon the train operation, but on the contrary,n Yfor reasons explained above, it is desirable in systems ot the intermittent type. there there are regular stops such as station stops, water tanks, and the like, special release magnets may be provided, i't desired, to remove the minimum speed restriction at once without waiting until the train has traveled to the end ot the block.

The low speed relay LS and its control, as just described, also Yfacilitates and simplities the control required to protect trains moving vfrom sidings on to the main track1 By reason ot' the provision oli the low speed relay LS, whenever the train stops on a siding it can not thereafter proceed at a speed greater than the restricted minimum speed until it passes a live reset magnet. Accordingly, a train coming out on to the main track from a siding is automatically restricted to a minimum speed, irrespective of whether the block on the main track is in theclear, caution., or danger condition. Hence it :ls n,

llO

to provide an operating inductor or equivalent means at each siding to assure the safe control ot' a train leaving that siding.

Entering and tcm/*flag non-frein control fem'.5120/y.-lleterring to Fig. et of the drawings, a section of tracl; has been shown equipped tor a change from train control territory to territory not equipped ttor train control. Three blocks K, L and M have been shown. the block K being equipiried for train control operation, the block L being equipped for a change from train control to nontrain control territory, while the block M is unequipped lor train control operation. The equipn'ient oi the exit end ot block K is identical with the tracltway equipment described in connection with Fig. 1, and for this reason a detailed description ot' this traclrway equipment will not be repeated. it being under stood that the operation o t the track relays, in ductors and reset devices is the same as that described in connection with Fig. 1. At the exit end ot the block L two spaced non-train control reset magnets CRl and CR2 are located. These reset magnets are oit the same construction as reset magnet R, but are continuously maintained energized by a battery 126. Slightly in advance of the non-control reset magnet CB1, and on the opposite side otl the tracly rails. is located a non-control operating inductor CC. This non-control inductor CC is ot the continuously active type, that is, it is composed of a. U-shaped core only, no winding beingprcsent. The noncontrol operating inductor C() is located approximately 100 'feet along the trackway 'from non-control reset niagnet CB2, for reasons which will be apparent as the description progresses.

Assuming a train to be trave-lling in block L at speed, that is above the low speed limit assumed to be 3 miles per hour and below the high speed limit assumed to be G0 miles per hour, the ear-carried reset receiver RR first. pas. over the energized non-control reset magnet CRL. This operates in a manner deribed above to reset the distance cams 69, TO, 1T and 1S, so placing the car-carried apparatus in its normal condition. lit the distance cam shaft 46 is already in its normal posit ion, the reset magnet CR1 will have. no ellect on the car-carried apparatus. The operating receiver RO next passes over the acti re non-control operating inductor CO, Vwhich starts the ldistance cams in operation thriiugh circuits and relays which have been descril'red. After 125 feet ot' travel, the contacts 12T ot the distance cam 69 will be closed. 1t should be noted that at this point the primary relay PT and the secondary relay ST have been re-encrgized through the closing of the contacts 86 and 37 ot the distance cam 70, which contacts close after 100 ilfeet of car Y' 'from the point at' which the canis are. explained above.. At this point the.

reset receiver RR will be energized from the non-control resetV magnet CE2, and the reset relay RT and the cam control ielay CC will be energized. It at this point the acknowledging relay Acli; is energized by depressing the push button PB, a circuit through the non-train control relay NC will be closed. This circuit may be traced as follows from the battery terminal C, through the winding of the non-control relay NC, wires 128 and 129, contact 130 of the acknowledging relay,

kwire 131 through the contacts 127 of the distance cam 69, wire 132 and contact 118 of the cam control relay CC to the battery terminal B. lVliile the energization of the earn control relay CC will cause the energization ot the cam starter magnet CS and the subsequent opening of the contacts 127 of the distance cam 69 at the same time that the noncontrol relay NC is energized, the relay NC is so proportioned and arranged that it will act more quickly than the cam starter magnet, and so will operate its contacts 133 before the energizing circuit of its winding has been broken.

The energization of the non-control relay NC will attract its Contact 133, closing a stick circuit through this relay which may be traced as follows from the battery terminal C through the winding of the non-control relay NC, wires 128 and 134, Contact 133 of the non-control relay NC, wires 144 and 13 through the armature 82 of secondary relay ST to the battery terminal B. The energization et the non-control relay NC closes its contacts 136, 137, and 138. The closing ot the contact 136 maintains the stick circuit through the penalty relay PR closed as is evident from the drawings. The closing of the contact 137 maintains the stick circuit of the low speed relay LS closed, regardless of t-he train speed. The closing of the contact 138 maintains an energizing circuit through the electro-pneumatic Valve, and thus prevents an automatic brake application. then the non-control relay NC is energized the cab signal 139 is displayed, indicating to the engineer or train operator that the automatic train control apparatus is no longer in effect. The train may now proceed over trackway not equipped for automatic control without delay by automatic brake application.

Referring now to Fig. 5, the traekway equipment vand part of the car-carried apparatus comprising another modification of the means for energizing the non-control relay NC and so rendering the car-carried brake control apparatus inactive has been shown. Referring particularly to the trackway equipment, the block V, and the ends of the adjacent blocks U and lV have been shown, the blocks U and V being the .last two blocks in a section el? track'way which is equipped for automatic train control, and the. block W being the. tiret block in an unequipped section ot trackway. The equipment in the blocks 'U and l is identical with that shown in Fig.

l described above. At the exit end ot the bloc-k V, on the le'lt side oi the track rails, is lo `ated an excess energy reset magnet RE which is similar to the reset magnet R, but is permanently energized with an excess amount o'tl current 'from the battery 151. For the sake o't simplicity, only that'portion of the carcarried apparatus which ditl'ers from the carcarried equipment shown in Fig. 3 has been disclosed in Fig. 5. It is to be understood that a diagram ol the complete car-carried apparatus embodying the inodil'ied method of rendering the brake control apparatus inactive could be obtained by a combination ot' Figs. 3 and 5.

A railway vehicle has been conventionally 'represented at 152 in the block U, and is equipped with an. operating receiver RO and a reset receiver RR, identi al withthe carcarried receivers described in connection with Fig. 3. The reset receiver RR is connected in series with the reset relay RT through a circuit which may he traced 'tollows z---From the winding 89 of the reset receiver RR, wires 148 and 91, the winding ot reset relay RT, wires 90, 1449 and 153, back contact and contact linger -l ot the acki'iowledging relay Acli, and wires 1t 5 and 156 to the winding 88 ot the reset receiver 1t will be observed thatl the Contact finger 154v ot the acknowledging relay Acli normally shunts the resistance unit 157, and that when this relay is energized to attract the linger 1.54, the resistance unit 157 is included in the series circuit trom the reset receiver RR to the reset relay RT, just traced. The pick-up circuit for the non-control relay NC is con'ipleted through a contact linger 1.61ct the reset relay RT, wire 1GO and contact linger 130 ol the acknowledging relay Acli as clearly shown in the drawings, the distance cam ('39 and its associated contact 127 shown in Fig. 3 being omitted in the moditication shown in Fig. 5. All other circuits and devices oit the carcarried apparatus shown in Fig. 5 are identical with those shown in Fig. 3, and as their arrangementvand operation has been described above, no further description of these circuits and devices is necessary.

lhen a Vtrain equipped with the moditied apparatus shown in Fig. 5 approaches the exit end of the block V which is the last block in a section oit trackway equipped. tor automatic train control, the engineer, knowing by some ,suitable wayside indication that he is approaching a section ol" unequipped trackway, depresses the push but ton PB and so en ergizes the acknowledging relay Acli, causing its contact linger 154 to be attracted, and inserting the resistance unit 157 in the circuit to the reset relay RT. The reset receiver now passes over the excess energy magnet RE and, as this magnet is supplied with an excess amount ot current, the reset relay RT will be energized in spite of the resistance oil'ered by the unit 157 in its energizing circuit, and t-he contact linger 161 of the reset relay RT will be attracted, closing its front contact and completing a pick-up circuit 'tor the non-control relay NC through the contact finger 130 and the trout contact ot the acknowledging relay Ack, which circuit is obvious `from the drawings. Once energized, the non-control relay NC will remain energized through its stick circuit as hereinhetore described, and will. maintain its contact lingers 133, 13G, 187 and 138 attracted., energizing the penalty relay PR, the low speed relay LS and the electro-pneumatic valve lill-7V, so that the train may proceed unrestricted in the unequipl ed section of trackway.

Tl the engineer attempts to release the train from the restriction o'l the automatic brake apparatus by depressing the push button PB while. the train is passing over the normally energized reset magnet R, the resistance unit 1.57 will be innnediately inserted in the circuit from the reset receiver RR to the reset relay RT, and the energy delivered 'from the reset magnet R to the reset receiver RR will not be sutlicient to energize the reset relay RT because ot the presen ce of this resistance unit in this circuit. lt is thus evident that the en gineer may render the car-carried brake control apparatus inactive only when passing an excess energy resent magnet and, as these magnets are located only at points where it is desired to travel over unequipped sections ot trackway, the engineer may not avoid the restrictions ot the automatic control when travelling in equipped territory.

llVhen a train equipped with either ot the modilied 'lorins ot non-control set up shown in Figures 3 and 5 returns to a section oit trackway equipped 'for automatic train ccntrol, and passes over an operating inductor which is in the active condition, the operating receiver RO will he actuated in a manner hereinbeliore described, dro pipingl primary relay PT and the secondary relay ST, and so breaking the stick circuit to the noncontrol relay NC. This will drop the contacts 133, 13G, 1.37 and 1.38, and the train may now proceed under automatic control in the manner described.

It may be desirable to place the train control apparatus in an active condition immediately upon the entrance of the train into equipped territory, beitore an active operating inductor is encountered. In this case, a special inductor, similar to the inductor C() and continuously in an active condition, may be located at `the entrance to each section ot traekway which is equipped 'for automatic train control.

lt is to be understood that the specific circuits, devices and arrangements shown are used for the purpose ot disclosing the invention and not for limiting its scope, and that many changes, modifications and improvements mi ght be made without departing from the spirit of the invention. For instance, alternating current may be used' t'or energizing the reset magnet instead of direct current from a battery, as shown, a condenser being' preferably connected .i n series with the winding ot said reset magnet in that case.

lVhat is desired to be secured by Letters Patent ol the United States is l. ln an automatic train controlV system ot the type in which control influences corresponding to trallie conditions are inductively transmitted from the trackway to a movinbr vehicle, 'ar-carried means for controlling the speed ot the vehicle in accordance with traliic conditions, and associated means, operated by a car-carried speed responsive device, for imposing a low speed restriction when the speed ot the vehicle drops below a predetermined minin'ium.

2. In an automatic train control' system, means for communicating impulses corresponding to tratlie conditions from elements located at spaced points along' the track rails to inductive car-carried elements; means actuated by said car-carried elements tor limiting' the speed ot' the train in accordance n'ith trallie conditions, additional car-carried speed controlled means for bringingl the train to a stop whenever the train speed drops below a Lgiven minimum value, and manually actuated means, which, it actuated when the train passes below said minimnmspeed value,

will prevent thel automatic stopping ot the train. Y

3. In an automatic train control system, means partly located on a vehicle and partly located at spaced points along' the track rails t'or inductively transmitting control influences corresponding to traliic conditions to speed controlling` apparatus on the vehicle, further means, controlled by the speed ot the vehicle, tor bringing the vehicle substantially to a stop if the train speed drops below a givenr speed, manually actuated means for substitutinga low speed limit lor said stop, and a distance controlled device lor bringingl the vehicle to a-stop it' said manually actuated means is lett in an active condition for more than. a given distance of vehicle travel.

il. In an automatic train control system, means partly located on a vehicle and partly located at spaced points along' the track rails for inductively transmitting' control influences corresponding to tratlic conditions to speed controllingT apl'iaratus on the vehicle, iturther means Yfor bringing' the vehicle substantially to a stop when an influence corresponding to unfavorable tra'tlic conditions is transmitted, manually actnable means for substitut-ing a permissive speed restriction tor said stop, and adistance eontrol'devce for bringingr the vehicleto a stop it said manually actuable means is maintained actuated 'for' more than a given distance ol vehicle travel.

5. In an automatic train control system, inductive trackway elements, located at spaced points along both sides ol the track rails, said inductive trackway elements on one side oi the tra-ck rails being normally electrically energized and said ela-)ments on the other side ot the track rails being` normally inert, apparatus carried on a y'railway vehicle for respending;V to intluences from said trackway elements, and lor contro-lling` the movement ot' the vehicle in response to the influences so received and 'further means located alongl the track rails for placing' said vehicle carried apparatus in an inactive condition.

t5. ln an automatic train control system, vehicle-carried ap paratus including a permissive speed device normally setting up a permissive speed limit, and when initiated A:},'raduall y` setting up more restrictive speed limits, trackway and vehi'cle-carried elements "lor transmitting influences corresponding' to trallic coinflitions to control apparatus for fend permissive speed device, speed governed means 'lor briining the vehicle substantially to a stop when the train speed has been reduced liielow a given lovv speed, and 'further tra cknf'ay elements acting,l to render said permissive speed device and'said speed governed means lnacti ve while the vehicle is travelling over certain sections ot tra-ckway.

'4". In an automatic train-control system, vehiclc-carritul apparatus tor automatically limiting the vehicle speed, inductive means comprising coils mounted on the vehicle and devices mountedA on the trackava'v tor communicating; control influences cori- A`pending;v to tratlic conditions to said speed limiting apparatus, said trackway devices comprising' normally energized electro-magnets located on one side ol the track rails, and inductor elements requiring' no energy located on the other side of the track rails, further track- Yay devices comprising two constantly energized'electro-magnets located on one side of the track rails, and a constantl active inductor clement located on the other side oit the track rails at a point betiveensaid two constantly energized electro-maguets, and a predetermined distance of vehicle travel in advance ot' the second ot' said indnctor elements said 'further trackway devices acting' to render said speed limiting apparatus inactive.

S. ln an an tomatic train control system, cararried apparatus tor normally controlling the progress of a vehicle auton'iatically in accordance vvith influences corresponding to traiiic conditions, means tor communicating said influences from the trackway to the moving vehicle, comprising trachvfay inductive devi'es and car-'carried inductive c evices, a ear-carried relay, manually operable means llll lflll for energizing said relay, 'further trackway devices comprising two constantly energized magnets located on one side of the track rails and spaced apart, and a constantly active inductor located on the other side of the track rails and at a point between said two constantly energized magnets and a predetermined distance ot vehicle travel in advance ot the second ot said constantly energized magnet, and associated ar-carried means, active when said manually operable means is actuated at a point ol car travel near said second constantly energized magnet, to render said automatic controlling apparatus inactive.

9. In anautomatic train control system,cara-rried apparatus for controlling the movement or' a train in accordance with inuences corresponding to trat'lic conditions ahead, trackway and car-carried inductive means tor communicating said influences from the trackway to said car-carried apparati'ls, a stick relay associated with said car-carried apparatus and adapted to drop its contacts under certain control conditions, a cam operated by the distance ot travel of the vehicle and initiated by the dropping Ot said stick relay, said distance cam closing a circuit to re-energize said stick relay after a given distance .ot car travel from the point at which said stick relay contacts were dropped, and manually actuated means, active after a Yturther dist-ance of travel from the point at which said stick relay contacts were dropped, to re-energize said stick relay.

l0. ln an automatic train control system, vehicle-carried apparatus including a stick relay 'for normally controlling the progress oli the vehicle automatically in accordance vwith influences corresponding to tra'fiie conditions, traekway influences from the trackway to the moving vehicle, and for de-energizing said stick relay under certain traiic conditions, a manually energized acknowledging relay associated with said car-carried apparatus. 'further inductive trackway means for rendering said controlling apparatus inactive ot said acknowledging relay is energized while the vehicle is passing said further traekway means, al distance operated device for re-energizing said stick relay ata given distance of vehicle travel from the point at which it was fle-energized, and further means, including a front contact ot said acknowledging relay, 'for re-energizing said stick relay a'l'ter the vehicle has travelled more than said given distance 'from the point at which said stick relay was cle-energized.

l1. n an automatic train control system, car-carried apparatus ior normally controlling the ear speed in accordance with influences corresponding to traflic conditions, car and trackvay inductive elements :tor transmitting inlluences to the moving car, a manually energized eelfzeo'wlfalgag arr-,-

lay, low speed stick relay, and a penalty relay, associated with said car-carried apparatus, speed governed means, active when the car speed drops below a given minimum, to (le-energize said low speed stick relay, and to cle-energize said penalty stick relay, means electrically associated with said penalty stick relay for bringing the car to a stop wnen said penalty stick relay is Cle-energized, a circuit closed by the energization of said acknowledging relay to prevent the de-energizat-ion of said penalty stick relay, and further speed control apparatus being substituted for said normally controlling apparatus by the deenergization of said low speed stick relay.

12. In an automatic train control system, ar-carried apparatus including a primary stick relay for controlling the progress otl the car in accordance with influences corresponding to tra'liic conditions ahead, inductive elements mounted partly on the car and partly on the trackway for communicating said influences to the moving car, said trackway elements acting to Cle-energize said pri- `mary stick relay under certain traflic conditions, a penalty stick relay, active when t eenergized to effect an automatic brake application,bringing the car to a stop, ,aid primary stick relay when fle-energized opening a circuit to said penalty stick relay, and an alternative circuit including the front contacts ot a manually energized acknowledging relay, for maintaining said penalty stick relay energized when said primary stick relay is cle-energized, and thus preventing an automatic brake application.

13. In an automatic train control system for railways having a portion of their trackvway equipped for automatic train control and a portion not so equipped, vehicle carried control apparatus for cont-rolling the brakes of a train in accordance with control intlnences corresponding to traiiic conditions ahead, trackway and vehicle cai ied inductive elements each including an iron core` for transmitting said control influences to a moving vehicle, and other trackway elements eacn including an iron core supplied with an amount o'll energy in excess of the amount supplied to said first trackway elementsI` and acting with vehicle carried means to render said vehicle carried control apparatus inactive `while the vehicle is travelling in said unequipped portions of trackway.

lll. In Van automatic train control system, car-carried apparatus 'for controlling the brakes of a vehicle in accordance with influences corresponding to tratlic conditions ahead, means for communicating said influences roln the trackway to a moving vehicle comprising trackway inductive devices each including a magnetic core and car-carried inductive devices each including a magnetic core, a car-carried relay for rend in ear-carried href central appar CII Il t) and means for actuating said relay comprising manually controllable car-carried means and a trackivay inductivev device supplied With excess amount el' energy.

l5. ln an automatic train control system, car-carried apparatus for controlling the brakes ot a vehicle in accordance ivith control in tluences corresponding to traiiic conditions, means tor communicating said control influences from the trackn'ay toa movi ng vehicle comprisingl inductive car-carried devices and spaced inductive trackivay devices comprising cores ot magnetic material when in their active condition, a car-carried relay active when energized to render said brake control apparatus inactive. manually controllable means it'or energizing sa id relay only ivhen an exce. s amount ot energy is supplied to one ot said inductive car-carried devices, and a trackn'ay inductive device including a core oit magnetic material supplied with an excess amount of energy and acting' to communicate an excess amount ot energy to one ot said inductive car-carried devices, ivherehy said relay maybe energized by said manually controllable means only .vhen the vehicle passes said excessiv ly energized trackn'ay inductive device.-

16, ln an automatic train control system ha ving' a portion oli its trackivay equipped Ytor automatic control and a portion not so equipped, vehicle carried apparatus including a permissive speed device normally setting up a permissive speed limit and When initiated gradually setting up a permissive speed limit and ivhen initiated gradually setting up more restrictive speed limits, trackn'ay and vehicle carried devices for transmitting influences corresponding to tratlic conditions to the vehicle and lor controlling said permi..:ive speed device in accoroance'ivith said intlucncec, car-carried speed governed means lor imposing a constant minimum speed restriction when the, train speed has been reduced below a given low speed, and other trackivay elements, located at the entrance to said nnequipped sections ot traclvvav. and supplied with an excess amount ot en said other trackvvay elen'ients acting ivith manually controllable car-carried means to render said permissive speed device and said speed `governed means inactive. whereby said constant minimum speed restriction will not he imposed on a train travellingin said uneouipped sections ot tracl-n'ay.

i7. ln an automatic train control systems 'for railways having portions of their trackivay equipped `tor automatic train control and portions not so equipped1 vehicle carried apparatus including a permissive speed device for gradually setting up more restrictive speed limits vvhen initiated, trackivay and vehicle carried inductive devices .tor transmitting control influences corresponding' to trafc conditions to the vehicle and for controlling said permissive speed device in accordance with said control influences, car-carried speed governed means for bringing the vehicle substantially to a stop it' the train speed is reduced below a given minimum, manually controllable means for substituting a constant minimum speed restriction for said stop, and another tr: ckn'ay inductive device simplicd f'ith an excess amountof energy and vlocated at the entrance to said unequipped portions orn trackway and acting with said manually controllable means to render said permissive speed device and said speed governed means inactive, whereby said stop or said constant minimum speed restric-V tion are not ellicctive it the train speed is reduced below said given minimum While the train is travelling over said unequipped sections of trackway.

18. In an automatic train control system, track'ivay and vehicle-carried means Jfor transmitting influences corresponding to tratlic conditions to a movin vehicle, vehiclecarried apparatus 'tor causing an automatic brake application and bringing the vehicle to a stop in response to influences corresponding to unfavorable traliic conditions, manually actuahle means Yfor substituting a speed restriction for said stop it actuated before au influence corresponding to unfavorable tralilic conditions is received, and a distance controlled device for bringing the vehicle to a stop if said manually actuable means is maintained actuated tor more than a predetermined distance of vehicle travel.

19. An automatic train control system comprising, a normally energized electro-responsive brake control device connected in a stick circuit carried by a railway vehicle, means partly on the vehicle and partly along the track for momentarily opening said stick circuit, and manually operable means lor preventing opening' ot said stick circuit when manually operated, and means for restricting the progress of the vehicle it said manually operable. means remains manually operated during more. than a predetermined limited distance ot travel of the vehicle.

20. Railway tratlic controlling apparatus comprising, normally inactive automatic brake application mechanism on a vehicle, means controlled from the trackivay for set.- ting said mechanism into operation under unsafe tratlic conditions, and manually controllable means on the vehicle operable only tor a limited distance of travel of the vehicle to prevent said mechanism being set into operation from the trackivay, and Which itt operated through more than this limited distance itselt' effects a brake application.

2l. In a train control system, train controlled means on a vehicle having a normally closed operating circuit and an auxiliary retaining circuit, and manually operable means for closing the retaining circuit,

Cil

said manually operable means when operated opening` the operating circuit after a predetermined distance of travel of the vehicle after Such manual operation.

22. Railway traiiie controlled apparatus comprising, brake application means on a vehicle, devices located at intervals in the traekway and arranged to cooperate with said means to cause a brake application 1n the event of dangerous traflie conditions ahead, and manually operable means on the vehicle which may he rendered effective only through a given distance of travel of the vehicle te prevent a brake application due to such cooperation.

In tetimony whereof I aHix my signature.

FRANK L. DODGSON. 

